Punch press die holder with hand-operated retaining clamp

ABSTRACT

A punch press die holder assembly includes a die holder body with a fixed rim which partially surrounds an upwardly opening die receptacle within the die holder. The receptacle is dimensioned to receive a punch press die, especially of any various circular dies now in commercial use. Cooperating with the fixed rim portion of the die holder is a moveable clamp member that is a portion of the rim that has a centrally directed surface which contacts the die when the die is in place within the receptacle. A manually operable fastener is operatively connected to the moveable clamp member to hold the clamp member in a closed position for restricting the movement of the die and the fastener is movable by hand to an open position for releasing the clamp member and the die from the die holder so that the die can then be removed and replaced from one side by sliding it horizontally out of the die holder.

Applicants hereby claim the benefit of corresponding provisionalapplication Ser. No. 60/932,420, filed May 30, 2007 which isincorporated herein in its entirety.

FIELD OF THE INVENTION

This invention relates to the punch and die art and more particularly toan improved die holder for a punch press.

BACKGROUND OF THE INVENTION

In the punch and die art and particularly in the field of high-speedautomated forming and punching equipment for punching and forming aworkpiece, e.g., sheet metal and especially in the case of automatedturret punch presses, the punch presses are operated by computer torapidly perform a series of punching or forming operations sequentially.These punch presses which by themselves form no part of the presentinvention are typically provided with aligned upper and lower turretsthat rotate and are indexed intermittently between punching operations.The turrets may hold as many as a dozen or more separate punches thatare used in sequence for performing given punching or formingoperations.

In prior punch press die holders, the die is simply placed into a boredopening within the die holder and held in place by means of bolts,screws, or similar fasteners. Consequently, the placement and removal ofa die requires the use of hand tools and is therefore labor intensiveand time consuming. Although methods have been proposed to facilitatemore rapid removal of noncircular dies, i.e. those that are octagonal,rectangular, etc., these methods are not applicable to circular dies.Thus, there has been no way to manually remove or replace circular diesthat are in wide scale commercial use, that is to say without the use ofhand tools. In addition, the die must be inserted or removed from theside since the top of the die holder is obstructed by the upper turret.It has been calculated that in the course of a day, a typical punchpress operator may spend as much as two hours removing and replacingdies, and of course the press is out of production during this period.

In view of these and other shortcomings of the prior art, it is oneobject of the present invention to provide a way of reliably securing acircular punch press die within a die holder that allows removal andreplacement of the die without the use of hand tools.

Another object of the invention is to provide a hand-operated retainerthat is capable of enabling a circular holder die to be opened or closedmanually with what can be referred to as a flick of the wrist and tomake it possible for a die to be removed and replaced from the side ofthe die holder.

Another object is to provide a reliable hand-operated die retainer thatwill not accidentally release the die or allow it to slide upwardly outof its holder once locked in place manually.

Yet another object of the invention is to provide a manually operabledie-retaining device that can be retrofitted into a variety of existingpunch press tooling units including what is known as “thick turret”tooling as well as other tooling that employs circular dies.

Still another object is to provide a manually operable die holder thatprovides precision positioning, centering and angular orientation ofeach die, yet allows the die to be rapidly removed or replaced from theside of the die holder by means of simple hand movements.

These and other more detailed and specific objects of the presentinvention will be better understood by reference to the following Figs.and detailed description which illustrate by way of example but a few ofthe various forms of the invention within the scope of the appendedclaims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a top perspective view of one preferred form of the inventionas seen before a die is mounted therein;

FIG. 2 is a side elevational view partly in section along line 2-2 ofFIG. 1;

FIG. 3 is a side elevational view of the clamp of FIGS. 1 and 2;

FIG. 4 is a perspective view of the clamp with a die mounted in the dieholder;

FIG. 5 is an enlarged top plan view of a swivel that is used as a partof the die holder;

FIG. 6 is a perspective view of the swivel shown in FIG. 5;

FIG. 7 is a perspective view of an upper portion of the clamp of FIGS.1-4 with the die clamp member removed;

FIG. 8 is a side elevational view taken on line 8-8 of FIG. 7; and

FIG. 9 is a diagrammatic partial plan view of the clamp fastenerassembly on an enlarged scale;

FIG. 10 is a perspective view of another embodiment of the inventionshowing the die holder in a closed position and;

FIG. 11 is a perspective view of the die holder of FIG. 10 on anenlarged scale in an open position.

SUMMARY OF THE INVENTION

The invention provides a die holder assembly for a punch press thatincludes an annular die holder body with a circular rim which surroundsa die receptacle or socket within the die holder body. The receptacle isdimensioned to receive a punch press die, especially of any variouscircular dies now in wide scale commercial use. At the bottom of thereceptacle is a die-supporting surface for limiting the downwardmovement of the die during operation. A moveable clamp member isprovided as a part of the die holder. The clamp member has a centrallydirected circular clamping surface which is constructed to forcefullyengage the die when the die is in place within the receptacle. Amanually moveable fastener is operatively connected to the clamp memberto hold the clamp member in a closed position so as to prevent movementof the die but is able to be moved by hand to an open position forreleasing the clamp member so that it can be removed bodily or swung toone side to permit lateral removal of the die from the die holder. In apreferred form, the clamp member is an arcuate element which comprises asegment of the rim of the die holder that surrounds the die. The clampmember preferably comprises a segment of a circle having the same insidediameter as the outside of the die. The ends of the clamp member areeach connected to an adjoining portion of the rim. A connection at oneend of the clamp member comprises the manually operable fastener. Theother connection comprises a pivot or an easily separated connectionsuch as a hook and socket connection between the end of the clamp memberand an adjacent portion of the rim. In one form, the clamp member isprovided with a hook, e.g. at its left end, that is engaged in acomplementary shaped socket provided in an adjacent fixed portion of thedie holder. A preferred fastener comprises a manually movable cam memberat one end of a locking handle connected between the opposite end of theclamp and the die holder for forcefully moving the clamp to a closedposition for holding the die in place when the cam is moved manually toa locking position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Refer now to the Figs., and particularly to FIGS. 1-4 which show a punchpress die holder assembly 10 having an annular die holder body 12 with acircular rim 14 surrounding a generally cylindrical die receptacle ordie socket 16. The die holder 10 is mounted on the punch press (notshown) in any suitable manner, e.g. using a base plate 13 ofconventional well-known construction. The die holder 10 has a downwardlyextending inner sleeve 11 of conventional construction that is journaledfor rotation in the base plate 13. Sleeve 11 can be secured to the lowerportion of receptacle 16 by fasteners such as cap screws 15 (FIG. 1).The receptacle 16 is dimensioned to receive the circular punch press die18 (FIG. 4). At the bottom of the receptacle 16 of the die holderassembly 10 is a circular die-supporting surface 20 (FIGS. 1 and 7) forlimiting the downward movement of a die 18 when the die is mounted foroperation within the receptacle 16 as shown in FIG. 4. Receptacle 16 hasa centrally projecting locating pin 17 that fits into a slot 19 (FIG. 4)for holding the die 18 at the desired angular orientation. The dieholder 12 has a rim 14 that is divided into two parts including a fixedportion 14 a that is an integral part of the die holder 10, having aleft end 14 b and at the right end is provided a clamp hook 14 c. Thefixed rim 14 encircles approximately half of the die 18. The other halfis encircled by a removable segment which comprises an arcuate clampmember 22. The clamp member 22 has a centrally directed preferablycircular clamping surface 22 a which is constructed to contact the die18 when the die is in place and is equal in diameter to the outsidediameter of the die. A manually operable fastener assembly is removablyconnected to the clamp member 22 to hold the clamp member 22 in placewhen in a locking position but is capable of being moved by hand to anopen position for releasing the die from the die holder 10.

The clamp member 22 is in one form shown in FIGS. 1-9, a removablesegment of the rim 14 of the die holder 10. In this embodiment, at theleft end of the clamp member 22 is a connection comprising centrallydirected hook 22 b that is engaged in an outwardly opening socket 14 dat one end of the rim segment 14 a to provide a secure pivotalconnection that is easily separated to permit bodily removal of theclamp member 22. At the right end 22 c of the clamp 22 as seen in theFigures is the manually operable fastener assembly 24. The centrallyprojecting hook member 22 b is dimensioned to fit within the outwardlyfacing socket 14 d in the rim segment 14 a. As shown in FIG. 8, thesocket 14 d has a pair of generally upright sidewalls 14 e and 14 f. Thewall 14 f, which is closest to the end 14 b, is not vertical but istilted with its lower end closer to the clamp member 22. It can beinclined typically at an angle of about 2° to about 10° from a verticalline at 30 shown in FIG. 8. The mating wall of the hook 22 b issimilarly inclined to cooperate with the inclined wall 14 f of thesocket for preventing the clamp from sliding upwardly or moving whenlocked in place by a clamp fastener assembly 24 (FIGS. 3, 4 and 9) whichwill now be described while also allowing clamp 22 to be completelyremoved.

The clamp fastener assembly 24 includes a tension element, e.g. a capscrew 32, or other elongated fastener which extends through a slot 15 a(FIG. 7) in the die holder, then through a bored opening 22 d in theclamp 22, next through a washer 34 and a swivel 36. The swivel 36includes a vertical bore 36 a (FIGS. 5 and 6) for two vertical pivotpins 40 and 42 and a horizontal threaded bore 36 b for the screw 32. Theopen top of slot 15 a and connection with the clamp hook 14 c enable theclamp 22 to be removed from the side of the die holder 10 to permit sidereplacement of dies since the die receptacle is normally inaccessiblefrom the top. The screw 32 and swivel 36 are secured to a cam member 38by the vertically aligned upper and lower pivot pins 40 and 42. In thisway, the cam 38 is mounted for pivotal movement on the pins 40 and 42.

During use, the cam 38 can be positioned manually by an extensioncomprising an integral locking handle 38 a which, as shown in FIG. 1, isof arcuate shape to conform to the outer surface of the clamp 22 when ina closed position (FIG. 1). The right end of cam member 38 is bifurcatedto provide similarly contoured upper and lower cam elements 38 b and 38c (FIGS. 1 and 2).

The axis 38 d of the cam lobe, i.e. the high point 39 of the cam 38(FIG. 9), is positioned to pass somewhat beyond the center of screw 32to an over center position when the cam 38 is in its closed positionthereby locking the clamp member 22 in place and causing it to applypressure against the adjacent face of the die 18.

To assemble the clamp fastener assembly 24, the screw 32 which has anadjustment nut 46 near the head is passed through the bore 22 d of theclamp 22, is then threaded into the swivel 36 and is preferably bondedtherein, e.g. with Loctite®. The swivel 36 is then placed between thebifurcated ends 38 b, 38 c of the cam and pins 40 and 42 are inserted.The screw 32 is placed in slot 15 a and the adjustment nut 46 is thentightened against the bearing surface 15 c of the clamp hook 14 c to bealmost tight when the locking handle 38 a is in and “open” dotted lineposition of FIGS. 3 and 4. Before the clamp 22 is mounted on the dieholder 10, the die 18 is placed in the receptacle 16 from the side. Theclamp 22 is then placed over the die 18 and the locking handle 38 a ismoved manually to the closed position (from left to right as seen inFIG. 1 of FIGS. 1, 2 and 4) thereby drawing the right end of the clamp22 toward the right in the Figs. as its left end pivots about the hookand socket connection so that the inner surface 22 a of the clamp 22provides firm pressure against the abutting outer cylindrical outer wallof the die 18 as the cam 38 locks the clamp 22 in place, therebysecurely retaining the die in place within the die holder 10.

Refer now to FIGS. 10 and 11 wherein the same numerals refer tocorresponding parts already described. These Figures show a modifiedform of the invention which includes a pivoted handle extension and anadditional handle locking feature. In this embodiment, the curvedlocking handle 38 a is provided with a longitudinally extendingcentrally located slot 38 b to accommodate a curved handle extension 100that is held in place at its proximal end, at the left in this case, bymeans of a vertical pivot pin 102 that is able to slide longitudinallywith respect to handle 38 a, i.e. horizontally through upper and lowervertically aligned slots 104 and 106 in the handle 38 a. A ball plunger108 can be provided in extension 100 to act as a detent for holding thehandle extension 100 in its inactive or closed position (FIG. 10) byyieldably biasing balls upwardly and downwardly into sockets, only oneof which is shown at 110 in the handle 38 a. It can be seen that the dieholder 10 is provided with a slot 112 that opens upwardly and toward thefree end of clamp 22 to accommodate the lower end of the pin 102 forsecurely holding the handle 38 a in a closed position as shown in FIG.10 when the handle extension 100 is shifted toward the free end ofhandle 38 a. Handle 38 a is then pivoted inwardly to the closed positionof FIG. 10.

At the left end of the handle 38 a is provided a vertical pivot pin 41that extends through an enlarged head 116 of an eyebolt 118. Threaded onthe free end of the eyebolt 118 is a contoured nut 120 for holding theclamp member 22 in a closed die locking position when eyebolt 118 isplaced within the slot 15 a of the clamp hook 14 c. Nut 120 should beturned to adjust the clamping force of handle 38 a to about 25 lbs.Located approximately below the center of the clamp 22 is a finger slot122 that is cut into the body of the die holder. As can be seen, thefinger slot 122 opens upwardly as well as horizontally toward theposition taken by the operator for enabling the operator's finger to beinserted beneath the die 18 when the die is to be removed. Connected bymeans of a clamp adjustment screw 129 to the left end of rim 14 is amoveable clamp adjustment base 131 which allows the clamp 22 to be movedto the left or right, i.e. toward or away from the left end of the rim14 by turning the clamp adjustment screw 129. It will also be noted thatthe clamp member 22 is in this case provided with a clamp link 124 whichis connected to the clamp 22 by means of a pivot pin 126 and to theclamp adjustment base 131 by means of a second pivot pin 128.

When a die 18 is to be to removed, the die clamp arm extension 100 isswung outwardly to a releasing position (FIG. 11) about the pivot pin102 and by grasping the extension 100, the pin 102 is shifted toward theright in the Figures out of the retaining slot 112 thereby releasing thelocking handle 38 a which can then be pivoted outwardly(counterclockwise) as shown in FIG. 11 about pivot pin 41 therebyreleasing tension on the eyebolt 118 and allowing the bolt head 120 tobe released from the clamp hook 14 c. It will be seen that an opening130 which extends through the free end of the clamp 22 to accommodatethe eyebolt 114 is elongated vertically for enabling the bolt 118 topivot upwardly out of slot 15 a as the locking handle 38 a is pivoteddownwardly as seen in FIG. 11 thereby freeing the clamp 22 so that itcan be swung outwardly to an open position as shown in FIG. 11 so as toenable the die to be slid manually by the operator out of the die holder(toward the left in FIG. 11) without moving it either up or down. Thisoperation can be assisted by placing one finger in the finger slot 122below the die 18 to allow a slight lifting of the die to release it sothat it does not stick to the bottom due to oil suction. In this way thedie can be quickly removed by sliding it horizontally to one side eventhough the upper turret of the punch press (not shown) is closely spacedabove its upper surface. The link 124 by allowing more extended openingfacilitates removal of the clamp 22 and provides a wider opening for theremoval or replacement of the die.

To close the clamp 22 after the die 18 has been inserted, the clamp ismoved to the position shown in FIG. 10, the eyebolt and nut 120 are thenlowered by raising the free end of the clamp arm extension 100 so as toplace the eyebolt 118 in the slot 15a. The locking handle 38 a is thenpushed inwardly to the closed position shown in FIG. 10 so that thecamming action of the cam lobe 38 b at its right end as alreadydescribed above in connection with FIG. 9, draws the eyebolt 118 towardclamp 22, i.e. toward the left in the Figures thereby causing theclamping nut 120 to be forced tightly against the clamp hook 14 c. Theclamp arm extension 100 is slid to the right so that it can then bepivoted inwardly to the closed position shown in FIG. 10. The extension100 and pin 102 are then shifted to the left into the retaining slot 112thereby securely locking the clamp arm 22 in the closed position.

The invention is rugged in construction, reliable in operation, and willsecurely hold circular dies 18 in the die holder but yet can be openedquickly with a flick of the wrist using no tools by manually pivotingthe free end of the locking handle 38 a outwardly to remove tension onscrew 32 or bolt 118 thereby relieving the compressive force applied bythe clamp member 22 against the adjoining wall of the die 18. When theclamp 22 is swung away from body 12 of the die holder, the die 18 can beeasily withdrawn and replaced from one side whenever required. Thehandle extension 100 makes possible two important results at the sametime; it acts as a lock when the pin 102 enters the recess 112 and theease of opening and closing the die holder is substantially improvedsince the extension 100 is provided a greater moment arm. It was alsofound that the finger hole enables the die to be readily grasped foreasy removal by the operator.

The directions; up, down, horizontal, left, right, etc. herein are usedin a relative sense without limiting the spatial orientation of the dieholder.

Many variations of the present-invention within the scope of theappended claims will be apparent to those skilled in the art once theprinciples described herein are understood.

1. A punch press die holder assembly comprising, an annular die holderbody with a rim that extends around a portion of a die receptacle, thedie receptacle being dimensioned to receive a punch press die therein,said die holder assembly having a die support for limiting the downwardmovement of the die therein, a moveable retaining clamp member as a partof the die holder that has a centrally directed surface which ispositioned to contact the die and a manually moveable fastener assemblyoperatively connected to the clamp member to place the clamp member in aclosed position that restricts the movement of the die and the fastenerassembly is adapted to be repositioned by hand to an open position forreleasing the die from the die holder.
 2. The punch press die holder ofclaim 1 wherein the clamp member comprises a moveable segment of the rimof the die holder that contacts one side of the die.
 3. The apparatus ofclaim 1 wherein the clamp member has a pair of ends with connections toadjacent fixed portions of the rim at each such end thereof and themanually moveable fastener is operatively associated with a first one ofsaid connections.
 4. The apparatus of claim 3 wherein a second one ofsaid connections is a hook and socket connection between the clampmember and a portion of said rim adjacent thereto.
 5. The apparatus ofclaim 1 wherein the fastener assembly comprising a manually moveable cammember that is operatively associated between one end of the clamp andthe die holder for forcing the clamp into engagement with the die whenthe cam is moved manually to a locking position.
 6. A punch press dieholder assembly comprising, a die holder body with a rim partiallysurrounding a die receptacle therein, the receptacle being dimensionedto receive a punch press die therein, said die holder assembly having adie-supporting element for limiting the downward movement of the dietherein, a clamp member as a part of the die holder that has a surfacewhich is constructed to contact the die but is movable to provide anopening for access to the die from one side thereof, a fastener assemblyoperatively connected to the clamp member to move the clamp member to aclosed position for preventing removal of the die, the fastener assemblycomprises a manually moveable cam member that is engaged between theclamp and the die holder for forcing the clamp to a position for holdingthe die in place when the cam is moved manually to a locked position andthe cam has a handle that is moveable by hand to an open position forreleasing the clamp member and the die from the die holder.
 7. The punchpress die holder of claim 6 wherein the clamp member comprises amoveable segment of the rim of the die holder.
 8. The apparatus of claim6 wherein the rim has a pair of ends and the fastener assembly isconnected to one of said ends.
 9. The apparatus of claim 8 wherein ahook and socket connection is provided between the clamp member and asecond one of said ends for enabling the clamp member to be removedbodily from the die holder.
 10. A punch press die holder assemblycomprising, a die holder body with a rim and a die receptacle therein,the receptacle being dimensioned to receive a punch press die therein, amoveable clamp member as a part of the receptacle that has a centrallydirected surface which is constructed and arranged to contact the diewhen the die is in the die receptacle, a manually moveable fasteneroperatively connected to the clamp member to hold the clamp member in aclosed position that prevents removal of the die and the fastener ismoveable by hand to an open position for releasing the die from the dieholder, the clamp member has a pair of ends and the fastener isconnected to one of said ends, and a second one of said ends ispivotally associated with the die holder.
 11. A die holder for a punchpress comprising a die holder body that is divided into two cooperatingmoveably related die holding portions confronting one another, each ofthe die holding portions of the die holder has a centrally facingsurface constructed and arranged to contact a mating outer surface of adie, at least one of the die holding portions is a clamp that ismoveably mounted on the die holder with a pivotal connection at one endthereof for enabling the clamp to pivot with respect to the other dieholding portion, a manually operable fastener that has a locking handlefor being grasped by an operator for forcing an end of the moveableclamp member that is opposite the pivotal connection toward a lockingposition so as to exert pressure on the die for retaining the die inplace within the die holder.
 12. The apparatus of claim 11 wherein thelocking handle has a cam member thereon with a lobe that is operativelyassociated with the die holder for tightening the clamp member when thelever arm is moved to a locking position.
 13. The punch press die holderof claim 11 wherein the clamp member comprises a removable arcuatesegment of the rim of the die holder.
 14. The apparatus of claim 11wherein the clamp member has a pair of ends, each with a connection to aportion of the die holder, the manually operable fastener comprises oneof said connections and the other of said connections comprises a hookand socket or pivotal connection between one end of the clamp member anda portion of the die holder adjacent thereto.
 15. The punch press dieholder of claim 1 wherein the manually moveable fastener assemblycomprises a locking handle and a handle extension is pivotally connectedto the locking handle by a pivot pin.
 16. The punch press die holder ofclaim 15 wherein the die holder has a retaining slot for the pivot pinto retain the clamp member in a closed position.
 17. The punch press dieholder of claim 1 wherein the clamp fastener assembly has an eyeboltconnected to a free end thereof with a clamping nut threaded on one endthereof for engagement with a clamp hook located on said die holderbody.
 18. The punch press die holder of claim 15 wherein the clampmember has a clamp link pivotally connected between a proximal endthereof and a rim of the die holder body.
 19. The punch press die holderof claim 18 wherein a moveable clamp adjustment base is adjustablyconnected between the link and the rim of the die holder.
 20. The dieholder of claim 1 wherein the die support is provided with a finger slotto facilitate manual removal of the die from the die holder.
 21. The dieholder of claim 1 wherein the die holder has a finger slot in a diesupporting surface that opens outwardly in a horizontal direction andopens upwardly to expose a lower surface of a die.
 22. A die holder fora punch press comprising, a die holder body having a socket forsupporting a die therein, a clamp member proximate the socket forengaging and holding the die in the socket, a manually moveable armmember mounted upon the die holder and being operatively associated withthe clamp member for moving the clamp member into a die-retainingposition when the arm member is moved manually to an operating positionand said arm member releasing the die when the arm member is movedmanually away from the operating position such that the clamp member isthen moveable away from the die-retaining position to provide an openingfor access to the die at one side thereof for removing the die from thedie holder.
 23. The die holder of claim 22 wherein one end of the clampmember is connected to the die holder body by a clamp hook or a pivotalconnection for supporting said one end of said clamp member on the dieholder body.